Summary of Activity Related to Goodwill (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Goodwill And Intangible Assets [Line Items]
Goodwill, Gross Carrying Amount Beginning Balance	$ 88,116
Increase in goodwill due to Bolt’s acquisition of Superior Access	2,540
Goodwill, Gross Carrying Amount Ending Balance	90,656
Goodwill, Accumulated Impairment Losses Beginning Balance	(304)
Goodwill, Accumulated Impairment Losses Ending Balance	(304)
Goodwill, Net Carrying Amount Beginning Balance	87,812
Increase in goodwill, Net Carrying Amount	2,540
Goodwill, Net Carrying Amount Ending Balance	$ 90,352